My 37 year old adult son has been at my ex-wifes house for over a year. He does not pay rent, does not have a job and has a warrant for his arrest on a DUI charge from 2 years ago. He lost custody of his 3 children who are living with their maternal grandparents. He owes more than $40,000 in past due child support.

How can he be removed from my ex-wife's home legally and permantly? My ex-wife wants him out so she can have her space and life back. The house is located in the Washington state.